Author Topic: x100 Gen Purpose Amp for lab use, 1st attempt.  (Read 1216 times)

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Offline InsatmanTopic starter

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x100 Gen Purpose Amp for lab use, 1st attempt.
« on: February 20, 2018, 04:39:44 am »
Hello,  I set about building an x100 amplifier mainly to measure noise on power supplies where my scope runs into the noise floor.   This is my first attempt.   Bandwidth is -3dB at 185kHz.  I hope to improve this by using a better op-amp on order from Digikey.   Noise floor with the input terminated 50ohm is about 2mV pk-pk.  This could be general noise from my lab, the scope or the cheap cable I used as well as the op-amp.  Nevertheless, this equates to roughly 20uV on the input, meaning the amp is only useful for ~100uV of noise or above without averaging.   A low-pass filter of ~90kHz was built into the unit and can be switched in and out using a toggle switch.  The filter is an active type using two sections of the quad-op-amp.   The noise floor is significantly higher when the filter in on, which surprised me.   I intend to play with the circuit and see if this can be improved.  Your comments, questions and advice are solicited.
« Last Edit: February 20, 2018, 06:29:13 am by Insatman »
Retired Pulsed Power Engineer/Physicist...now I just dabble in electronics
 
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Online PartialDischarge

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Re: x100 Gen Purpose Amp for lab use, 1st attempt.
« Reply #1 on: February 20, 2018, 06:21:50 am »
Very nice project. For this application im fortunate enough to own a 7104 with a 7A22 plugin :)
 

Offline InsatmanTopic starter

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Re: x100 Gen Purpose Amp for lab use, 1st attempt.
« Reply #2 on: February 20, 2018, 07:12:59 am »
Very nice project. For this application im fortunate enough to own a 7104 with a 7A22 plugin :)
Ahh...I remember using a 7104 when they first came out early in my career.   We had 7A22s as well but didn't use them much because of the type of work we were doing.  The micro-channel plate CRT was great for capturing fast pulses on film back in the day.
Retired Pulsed Power Engineer/Physicist...now I just dabble in electronics
 


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